Semiconductor image sensors are used to sense radiation that includes, for example, visible light. Complementary metal-oxide-semiconductor (CMOS) image sensors and charge-coupled device (CCD) sensors are widely used in digital cameras and mobile phone cameras. These sensors utilize an array of pixels located in a substrate, where the pixels include photodiodes and transistors. The pixels absorb radiation projected toward the substrate and convert the absorbed radiation into electrical signals, and these electrical signals are used in forming digital images. Tone mapping techniques may be used in transforming digital images to produce images that are more visually appealing to a viewer. Tone mapping techniques are used, generally, to map one set of colors or image characteristics to another set of values.